This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The goal of this project is to test, optimize and develop NMR experiments for studying RNA molecules and protein-RNA complexes on high-field instruments, equipped with cryogenic probes. In particular, we are studying large RNA molecules that require carefully designed and calibrated experiments for chemical shift assignments and extracting structural information, such as experiments for measuring RDCs in partially aligned media and for identifying H-bonded nucleotides. For smaller RNA molecules, we are attempting to apply our reduced-dimensionality approach, HIFI, for speeding up the data collection of multidimensional spectra needed for resonance assignments. We are also developing fast experiments to use for the studying of fast dynamic processes, such as conformational changes that take place upon binding of RNA with Magnesium. Finally, we are also developing new methods for studying protein-RNA complexes where we want to look at the interface by taking advantage of the differential labeling to selectively saturate one of the components and look for cross-saturation transfer across the intermolecular contact plane.